The present invention relates to thermoplastic polyimide and polyketone elestomers which are characterized by high temperature resistance and high fuel, oil and chemical resistance. These elastomers are particularly useful in the automotive industry where they may be used to mold hydraulic hose, pulleys, brackets, engine mounts and the like.
Polyimides and polyketones are known in the art, but previous polymers do not have the thermal and chemical resistance required for many uses particularly uses in the automotive industry where the temperature requirements for many engine accessories have increased dramatically in recent years.
Polymers formed by Michael (nucleophilic) addition of a bismaleimide are known in the art. White, J. E. et al., "Reactions of Diaminoalkanes with Bismaleimides: Synthesis of Some Unusual Polyimides," J. Appl. Poly Sci., 29, 891-99 (1984) discloses that polyimide elastomers can be obtained by reacting diaminoalkanes having flexible backbones with aliphatic and aromatic bismaleimides. Examples of the diaminoalkanes are 1,8-diaminooctane, N,N-dimethyl-1,6-hexanediamine.
U.S. Pat. No. 3,741,942 to Crivello (1973) teaches a polyimide obtained by reaction of a bismaleimide and a dithiol.
Bismaleimides have also been used to crosslink unsaturated rubbers as described in U.S. Pat. No. 2,989,504 to Little (1961), and they have been reacted with diamines by Michael addition in making fibers and molded articles as described in U.S. Pat. No. 2,818,405 to Kovacic (1957), U.S. Pat. No. 3,658,764 to Lyon (1972), U.S. Pat. No. 3,767,626 to Bron (1973), and U.S. Pat. No. 3,878,172 to Bargain et al. (1975), and re 29,316 to Bargain et al. (1976).
U.S. Pat. No. 3,738,967 to Crivello (1973) teaches that polyimides can also be prepared by a nucleophilic addition reaction of a bismaleimide and hydrogen sulfide. These polyimides are disclosed as being useful in molding, insulation, and coating. Another class of polyimide is obtained by reacting a bismaleimide with a diamine and then a sulfide or dithiol according to U.S. Pat. No. 3,766,138 to Crivello (1973).